Theory of chiral modulations in confining structures: epitaxial films of cubic helimagnets

限制结构中的手性调制理论：立方螺旋磁体的外延膜

• 批准号: 240641318
• 负责人: Professor Dr. Alexei N. Bogdanov
• 金额: --
• 依托单位: Institut für Theoretische Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/240641318?language=en
• 关键词: Theory; chiral; modulations; confining; structures

Recently synthesized epitaxial thin films of cubic helimagnets with non-centrosymmetric B20 structure (MnSi, FeGe, and others) represent a novel class of nanomagnetic systems exhibiting many physical phenomena unknown in bulk helimagnets. In particular, nanolayers of cubic helimagnets enable the observation of specific particle-like structures (skyrmions) predicted theoretically more than twenty years ago and the field-induced unwinding of helicoids via quantized steps. Our recent studies show that in nanolayers of cubic helimagnets the interplay between intrinsic chirality, structural confinement, and surface/interface induced interactions leads to the formation of specific confined chiral modulations which fundamentally differ from those commonly observed in bulk helimagnets. The aim of the project is to give a comprehensive theoretical description of confined chiral modulations and, thus, to establish physical relations between specific effects arising in cubic helimagnet nanolayers and peculiarities of their structures. Within the standard micromagnetic theory of helimagnetism rigorous solutions for helical and skyrmionic modulations in thin layers of cubic helimagnets will be derived in broad ranges of the thermodynamic parameters. Our theoretical findings will be used to construct magnetic phase diagrams for nanolayers of cubic helimagnets with different types of induced magnetic anisotropy. These results will be applied for detailed analyses of recent experiments in epitaxial films of MnSi and FeGe and to elucidate complex magnetization processes observed in these systems. They also should provide the theoretical basis for the emerging nanophysics of confined chiral modulations and supply practical recommendations for future investigations.

最近合成的具有非中心对称 B20 结构（MnSi、FeGe 等）的立方螺旋磁体的外延薄膜代表了一类新型纳米磁性系统，表现出许多块状螺旋磁体中未知的物理现象。特别是，立方螺旋磁体的纳米层使得能够观察二十多年前理论上预测的特定粒子状结构（斯格明子），以及通过量子化步骤由场引起的螺旋解旋。我们最近的研究表明，在立方螺旋磁体的纳米层中，固有手性、结构限制和表面/界面诱导的相互作用之间的相互作用导致了特定的受限手性调制的形成，这与在块状螺旋磁体中常见的调制有根本的不同。该项目的目的是对受限手性调制进行全面的理论描述，从而建立立方螺旋磁体纳米层中产生的特定效应与其结构特性之间的物理关系。在螺旋磁学的标准微磁理论中，立方螺旋磁体薄层中的螺旋和斯格明子调制的严格解决方案将在广泛的热力学参数范围内导出。 我们的理论研究结果将用于构建具有不同类型感应磁各向异性的立方螺旋磁体纳米层的磁相图。这些结果将用于对 MnSi 和 FeGe 外延薄膜的最新实验进行详细分析，并阐明在这些系统中观察到的复杂磁化过程。他们还应该为新兴的受限手性调制纳米物理学提供理论基础，并为未来的研究提供实用建议。

项目成果

Surface twist instabilities and skyrmion states in chiral ferromagnets

手性铁磁体中的表面扭曲不稳定性和斯格明子态

• DOI: 10.1103/physrevb.90.014406
• 发表时间: 2014-05-21
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: S. Meynell;M. Wilson;H. Fritzsche;A. Bogdanov;T. Monchesky
• 通讯作者: T. Monchesky

The properties of isolated chiral skyrmions in thin magnetic films

磁性薄膜中孤立的手性斯格明子的特性

• DOI: 10.1088/1367-2630/18/6/065003
• 发表时间: 2015-08-10
• 期刊: New Journal of Physics
• 影响因子: 3.3
• 作者: A. Leonov;T. Monchesky;Niklas Romming;A. Kubetzka;A. Bogdanov;R. Wiesendanger
• 通讯作者: R. Wiesendanger

Internal structure of hexagonal skyrmion lattices in cubic helimagnets

立方螺旋磁体中六方斯格明子晶格的内部结构

• DOI: 10.1088/1367-2630/18/9/095004
• 发表时间: 2016-06-15
• 期刊: New Journal of Physics
• 影响因子: 3.3
• 作者: D. McGrouther;R. Lamb;M. Krajnak;S. McFadzean;S. McVitie;R. Stamps;A. Leonov;A. Leonov;A. Bogdanov;Y. Togawa
• 通讯作者: Y. Togawa

Chiral Surface Twists and Skyrmion Stability in Nanolayers of Cubic Helimagnets.

立方螺旋磁体纳米层中的手性表面扭曲和斯格明子稳定性。

• DOI: 10.1103/physrevlett.117.087202
• 发表时间: 2015-12-14
• 期刊: Physical review letters
• 影响因子: 8.6
• 作者: A. O. Leonov;A. O. Leonov;Y. Togawa;T. Monchesky;T. Monchesky;Alexei N. Bogdanov;Alexei N. Bogdanov;J. Kishine;J. Kishine;Y. Kousaka;Marina Miyagawa;T. Koyama;Jun Akimitsu;T. Koyama;Ken Harada;Shigeo Mori;D. McGrouther;R. Lamb;M. Krajnak;S. McVitie;R. Stamps;K. Inoue
• 通讯作者: K. Inoue